I suggest creating a list of questions that are important to you and start asking!

Can someone please suggest a cheap skiptracing software?

I'd suggest a rental verification as well.

Suggestions like driving by the houses weekly are silly, such trips serve no legitimate business purpose. 

These are great suggestions.  

If you’re serious about buying properties and doing real estate, then I would suggest working with the CPA that understands real estate even if the services cost more than your average H&R Block or some TurboTax program you can buy.

However if you aren't doing mass scale, we definitely suggest letting the contractor handle material purchasing.As long as the client has all of the materials at the jobsite, place them where they go, they are all the correct type/fit and there are all of the misc parts (adapters/special hardware/etc) needed to do the install.

Nothing is foolproof of course, but having another investor in your market make a suggestion at least gets us on the right foot. 

Suggest you do the same (even if they are two page documents).

There are a lot of other strategies one can try, but what you do is the lowest risk, the most predictable outcome and takes the least amount of time and energy.I always suggest to use an extra time an investor has to think about building or buying a business that generates cash to accelerate the growth curve.